In the canning industry, automated and semi-automated systems are employed for rapidly filling a large number of cans or other containers with food product. Because of the nature of most crops, the canning season itself is quite short, dependent upon the peak harvest time of the crops being canned. As a consequence, large volumes of foodstuffs must be processed and canned (or bottled) in a relatively short period of time. Thus, the speed and efficiency at which automated canning systems are operated is crucial to the cost effective production of the finished product.
Liquid products, such as juices are relatively simple to process; and a variety of efficient automated systems exist for transferring such products from large reservoirs or vessels into individual containers, which then are sealed and processed for ultimate delivery to a consumer. With respect to semi-solid products such as chiles, tomatoes, salsa and other products of similar consistency, efficient canning systems generally have not been available.
For canning semi-solid products such as diced chiles, salsa or the like, it has been the practice in the past to move the cans or containers to be filled by means of a conveyor past a fill position. At the fill position, it generally has been the practice to utilize a piston filler employing vacuum and cam devices to control the fill for each can located at the fill position. Such piston filler systems may have as many as fifty or more valves on one machine. All of these valves have gaskets and cams and many moving parts. As a consequence, mechanical failures can and do occur. When such failures occur, the filling machine must be shut down while repairs are made. Such down times are critical in view of the necessity of rapidly processing the foodstuffs which are to be canned.
The accuracy of the fill in piston type fillers also depends on the condition of the wear of the machine parts and the viscosity of the product itself. Because the viscosity can change with every batch of product, the fill varies substantially in weight from batch to batch, and even from one time period to the next, because of the variables which exist. Adjustment of piston type filler machines to fine tune the product fill is difficult, since in most such machines adjustment of one valve to fill more or less causes all of the other valves on the same machine also to fill more or less. Using of piston fill machines requires vigilant quality control to remove underweight or significantly overweight containers from the production line.
Another disadvantage which exists with respect to piston type filler machines used in canneries is that a large amount of spillage or dropped product occurs on these lines. As the fillers become worn and the tolerances of the various parts lose precision, significant amount of product can be lost. This product loss can be as much as 1,000 pounds per hour on each filler line. Since the product which is supplied to the cans has already undergone substantial processing (it is not raw product from the field), the cost of this wasted product is significant. Even if the piston type fillers at a plant are updated and are operating at peak efficiency, the inherent construction of these fillers is that there will be and is product loss. Even if only one ounce of product is lost per container, the total amount of product loss can be significant. For example, on a typical run it is possible to fill 250 cans per minute. At one ounce loss per can (with product value of 25 cents per ounce), on a line running for twenty hours a day, this amounts to a loss of $75,000 per day for such a line.
This is the loss for a relatively efficient line. It has been discovered that less efficient lines may lose over 1,000 pounds of product per hour, on each canning line.
It is desirable to provide an efficient distribution valve which is particularly suitable for food canning lines, which accurately fills the containers, which reduces spillage of product to a minimum, and which is mechanically simple to construct and operate.